/*
 * Copyright 2000-2017 JetBrains s.r.o.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.jetbrains.uast.values

interface UValue : UOperand {

  fun merge(other: UValue): UValue

  val dependencies: Set<UDependency>
    get() = emptySet()

  fun toConstant(): UConstant?

  val reachable: Boolean

  companion object {
    val UNREACHABLE: UValue = UNothingValue()
  }
}

fun UValue.toPossibleConstants(): Set<UConstant> {
  val results = mutableSetOf<UConstant>()
  toPossibleConstants(results)
  return results
}

private fun UValue.toPossibleConstants(result: MutableSet<UConstant>) {
  when (this) {
    is UDependentValue -> value.toPossibleConstants(result)
    is UPhiValue -> values.forEach { it.toPossibleConstants(result) }
    else -> toConstant()?.let { result.add(it) }
  }
}
